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Merge git://git.kernel.org/pub/scm/linux/kernel/git/wim/linux-2.6-watchdog
[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / kernel / trace / blktrace.c
blobbc251ed667248fb8c72a0dd59ddf3a9a42e1c23d
1 /*
2 * Copyright (C) 2006 Jens Axboe <axboe@kernel.dk>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License version 2 as
6 * published by the Free Software Foundation.
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this program; if not, write to the Free Software
15 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
16 *
17 */
18 #include <linux/kernel.h>
19 #include <linux/blkdev.h>
20 #include <linux/blktrace_api.h>
21 #include <linux/percpu.h>
22 #include <linux/init.h>
23 #include <linux/mutex.h>
24 #include <linux/slab.h>
25 #include <linux/debugfs.h>
26 #include <linux/time.h>
27 #include <linux/uaccess.h>
28
29 #include <trace/events/block.h>
30
31 #include "trace_output.h"
32
33 #ifdef CONFIG_BLK_DEV_IO_TRACE
34
35 static unsigned int blktrace_seq __read_mostly = 1;
36
37 static struct trace_array *blk_tr;
38 static bool blk_tracer_enabled __read_mostly;
39
40 /* Select an alternative, minimalistic output than the original one */
41 #define TRACE_BLK_OPT_CLASSIC 0x1
42
43 static struct tracer_opt blk_tracer_opts[] = {
44 /* Default disable the minimalistic output */
45 { TRACER_OPT(blk_classic, TRACE_BLK_OPT_CLASSIC) },
46 { }
47 };
48
49 static struct tracer_flags blk_tracer_flags = {
50 .val = 0,
51 .opts = blk_tracer_opts,
52 };
53
54 /* Global reference count of probes */
55 static atomic_t blk_probes_ref = ATOMIC_INIT(0);
56
57 static void blk_register_tracepoints(void);
58 static void blk_unregister_tracepoints(void);
59
60 /*
61 * Send out a notify message.
62 */
63 static void trace_note(struct blk_trace *bt, pid_t pid, int action,
64 const void *data, size_t len)
65 {
66 struct blk_io_trace *t;
67 struct ring_buffer_event *event = NULL;
68 struct ring_buffer *buffer = NULL;
69 int pc = 0;
70 int cpu = smp_processor_id();
71 bool blk_tracer = blk_tracer_enabled;
72
73 if (blk_tracer) {
74 buffer = blk_tr->buffer;
75 pc = preempt_count();
76 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
77 sizeof(*t) + len,
78 0, pc);
79 if (!event)
80 return;
81 t = ring_buffer_event_data(event);
82 goto record_it;
83 }
84
85 if (!bt->rchan)
86 return;
87
88 t = relay_reserve(bt->rchan, sizeof(*t) + len);
89 if (t) {
90 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
91 t->time = ktime_to_ns(ktime_get());
92 record_it:
93 t->device = bt->dev;
94 t->action = action;
95 t->pid = pid;
96 t->cpu = cpu;
97 t->pdu_len = len;
98 memcpy((void *) t + sizeof(*t), data, len);
99
100 if (blk_tracer)
101 trace_buffer_unlock_commit(buffer, event, 0, pc);
102 }
103 }
104
105 /*
106 * Send out a notify for this process, if we haven't done so since a trace
107 * started
108 */
109 static void trace_note_tsk(struct blk_trace *bt, struct task_struct *tsk)
110 {
111 tsk->btrace_seq = blktrace_seq;
112 trace_note(bt, tsk->pid, BLK_TN_PROCESS, tsk->comm, sizeof(tsk->comm));
113 }
114
115 static void trace_note_time(struct blk_trace *bt)
116 {
117 struct timespec now;
118 unsigned long flags;
119 u32 words[2];
120
121 getnstimeofday(&now);
122 words[0] = now.tv_sec;
123 words[1] = now.tv_nsec;
124
125 local_irq_save(flags);
126 trace_note(bt, 0, BLK_TN_TIMESTAMP, words, sizeof(words));
127 local_irq_restore(flags);
128 }
129
130 void __trace_note_message(struct blk_trace *bt, const char *fmt, ...)
131 {
132 int n;
133 va_list args;
134 unsigned long flags;
135 char *buf;
136
137 if (unlikely(bt->trace_state != Blktrace_running &&
138 !blk_tracer_enabled))
139 return;
140
141 local_irq_save(flags);
142 buf = per_cpu_ptr(bt->msg_data, smp_processor_id());
143 va_start(args, fmt);
144 n = vscnprintf(buf, BLK_TN_MAX_MSG, fmt, args);
145 va_end(args);
146
147 trace_note(bt, 0, BLK_TN_MESSAGE, buf, n);
148 local_irq_restore(flags);
149 }
150 EXPORT_SYMBOL_GPL(__trace_note_message);
151
152 static int act_log_check(struct blk_trace *bt, u32 what, sector_t sector,
153 pid_t pid)
154 {
155 if (((bt->act_mask << BLK_TC_SHIFT) & what) == 0)
156 return 1;
157 if (sector && (sector < bt->start_lba || sector > bt->end_lba))
158 return 1;
159 if (bt->pid && pid != bt->pid)
160 return 1;
161
162 return 0;
163 }
164
165 /*
166 * Data direction bit lookup
167 */
168 static const u32 ddir_act[2] = { BLK_TC_ACT(BLK_TC_READ),
169 BLK_TC_ACT(BLK_TC_WRITE) };
170
171 #define BLK_TC_HARDBARRIER BLK_TC_BARRIER
172 #define BLK_TC_RAHEAD BLK_TC_AHEAD
173
174 /* The ilog2() calls fall out because they're constant */
175 #define MASK_TC_BIT(rw, __name) ((rw & REQ_ ## __name) << \
176 (ilog2(BLK_TC_ ## __name) + BLK_TC_SHIFT - __REQ_ ## __name))
177
178 /*
179 * The worker for the various blk_add_trace*() types. Fills out a
180 * blk_io_trace structure and places it in a per-cpu subbuffer.
181 */
182 static void __blk_add_trace(struct blk_trace *bt, sector_t sector, int bytes,
183 int rw, u32 what, int error, int pdu_len, void *pdu_data)
184 {
185 struct task_struct *tsk = current;
186 struct ring_buffer_event *event = NULL;
187 struct ring_buffer *buffer = NULL;
188 struct blk_io_trace *t;
189 unsigned long flags = 0;
190 unsigned long *sequence;
191 pid_t pid;
192 int cpu, pc = 0;
193 bool blk_tracer = blk_tracer_enabled;
194
195 if (unlikely(bt->trace_state != Blktrace_running && !blk_tracer))
196 return;
197
198 what |= ddir_act[rw & WRITE];
199 what |= MASK_TC_BIT(rw, HARDBARRIER);
200 what |= MASK_TC_BIT(rw, SYNC);
201 what |= MASK_TC_BIT(rw, RAHEAD);
202 what |= MASK_TC_BIT(rw, META);
203 what |= MASK_TC_BIT(rw, DISCARD);
204
205 pid = tsk->pid;
206 if (act_log_check(bt, what, sector, pid))
207 return;
208 cpu = raw_smp_processor_id();
209
210 if (blk_tracer) {
211 tracing_record_cmdline(current);
212
213 buffer = blk_tr->buffer;
214 pc = preempt_count();
215 event = trace_buffer_lock_reserve(buffer, TRACE_BLK,
216 sizeof(*t) + pdu_len,
217 0, pc);
218 if (!event)
219 return;
220 t = ring_buffer_event_data(event);
221 goto record_it;
222 }
223
224 /*
225 * A word about the locking here - we disable interrupts to reserve
226 * some space in the relay per-cpu buffer, to prevent an irq
227 * from coming in and stepping on our toes.
228 */
229 local_irq_save(flags);
230
231 if (unlikely(tsk->btrace_seq != blktrace_seq))
232 trace_note_tsk(bt, tsk);
233
234 t = relay_reserve(bt->rchan, sizeof(*t) + pdu_len);
235 if (t) {
236 sequence = per_cpu_ptr(bt->sequence, cpu);
237
238 t->magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION;
239 t->sequence = ++(*sequence);
240 t->time = ktime_to_ns(ktime_get());
241 record_it:
242 /*
243 * These two are not needed in ftrace as they are in the
244 * generic trace_entry, filled by tracing_generic_entry_update,
245 * but for the trace_event->bin() synthesizer benefit we do it
246 * here too.
247 */
248 t->cpu = cpu;
249 t->pid = pid;
250
251 t->sector = sector;
252 t->bytes = bytes;
253 t->action = what;
254 t->device = bt->dev;
255 t->error = error;
256 t->pdu_len = pdu_len;
257
258 if (pdu_len)
259 memcpy((void *) t + sizeof(*t), pdu_data, pdu_len);
260
261 if (blk_tracer) {
262 trace_buffer_unlock_commit(buffer, event, 0, pc);
263 return;
264 }
265 }
266
267 local_irq_restore(flags);
268 }
269
270 static struct dentry *blk_tree_root;
271 static DEFINE_MUTEX(blk_tree_mutex);
272
273 static void blk_trace_free(struct blk_trace *bt)
274 {
275 debugfs_remove(bt->msg_file);
276 debugfs_remove(bt->dropped_file);
277 relay_close(bt->rchan);
278 debugfs_remove(bt->dir);
279 free_percpu(bt->sequence);
280 free_percpu(bt->msg_data);
281 kfree(bt);
282 }
283
284 static void blk_trace_cleanup(struct blk_trace *bt)
285 {
286 blk_trace_free(bt);
287 if (atomic_dec_and_test(&blk_probes_ref))
288 blk_unregister_tracepoints();
289 }
290
291 int blk_trace_remove(struct request_queue *q)
292 {
293 struct blk_trace *bt;
294
295 bt = xchg(&q->blk_trace, NULL);
296 if (!bt)
297 return -EINVAL;
298
299 if (bt->trace_state != Blktrace_running)
300 blk_trace_cleanup(bt);
301
302 return 0;
303 }
304 EXPORT_SYMBOL_GPL(blk_trace_remove);
305
306 static int blk_dropped_open(struct inode *inode, struct file *filp)
307 {
308 filp->private_data = inode->i_private;
309
310 return 0;
311 }
312
313 static ssize_t blk_dropped_read(struct file *filp, char __user *buffer,
314 size_t count, loff_t *ppos)
315 {
316 struct blk_trace *bt = filp->private_data;
317 char buf[16];
318
319 snprintf(buf, sizeof(buf), "%u\n", atomic_read(&bt->dropped));
320
321 return simple_read_from_buffer(buffer, count, ppos, buf, strlen(buf));
322 }
323
324 static const struct file_operations blk_dropped_fops = {
325 .owner = THIS_MODULE,
326 .open = blk_dropped_open,
327 .read = blk_dropped_read,
328 .llseek = default_llseek,
329 };
330
331 static int blk_msg_open(struct inode *inode, struct file *filp)
332 {
333 filp->private_data = inode->i_private;
334
335 return 0;
336 }
337
338 static ssize_t blk_msg_write(struct file *filp, const char __user *buffer,
339 size_t count, loff_t *ppos)
340 {
341 char *msg;
342 struct blk_trace *bt;
343
344 if (count >= BLK_TN_MAX_MSG)
345 return -EINVAL;
346
347 msg = kmalloc(count + 1, GFP_KERNEL);
348 if (msg == NULL)
349 return -ENOMEM;
350
351 if (copy_from_user(msg, buffer, count)) {
352 kfree(msg);
353 return -EFAULT;
354 }
355
356 msg[count] = '\0';
357 bt = filp->private_data;
358 __trace_note_message(bt, "%s", msg);
359 kfree(msg);
360
361 return count;
362 }
363
364 static const struct file_operations blk_msg_fops = {
365 .owner = THIS_MODULE,
366 .open = blk_msg_open,
367 .write = blk_msg_write,
368 .llseek = noop_llseek,
369 };
370
371 /*
372 * Keep track of how many times we encountered a full subbuffer, to aid
373 * the user space app in telling how many lost events there were.
374 */
375 static int blk_subbuf_start_callback(struct rchan_buf *buf, void *subbuf,
376 void *prev_subbuf, size_t prev_padding)
377 {
378 struct blk_trace *bt;
379
380 if (!relay_buf_full(buf))
381 return 1;
382
383 bt = buf->chan->private_data;
384 atomic_inc(&bt->dropped);
385 return 0;
386 }
387
388 static int blk_remove_buf_file_callback(struct dentry *dentry)
389 {
390 debugfs_remove(dentry);
391
392 return 0;
393 }
394
395 static struct dentry *blk_create_buf_file_callback(const char *filename,
396 struct dentry *parent,
397 int mode,
398 struct rchan_buf *buf,
399 int *is_global)
400 {
401 return debugfs_create_file(filename, mode, parent, buf,
402 &relay_file_operations);
403 }
404
405 static struct rchan_callbacks blk_relay_callbacks = {
406 .subbuf_start = blk_subbuf_start_callback,
407 .create_buf_file = blk_create_buf_file_callback,
408 .remove_buf_file = blk_remove_buf_file_callback,
409 };
410
411 static void blk_trace_setup_lba(struct blk_trace *bt,
412 struct block_device *bdev)
413 {
414 struct hd_struct *part = NULL;
415
416 if (bdev)
417 part = bdev->bd_part;
418
419 if (part) {
420 bt->start_lba = part->start_sect;
421 bt->end_lba = part->start_sect + part->nr_sects;
422 } else {
423 bt->start_lba = 0;
424 bt->end_lba = -1ULL;
425 }
426 }
427
428 /*
429 * Setup everything required to start tracing
430 */
431 int do_blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
432 struct block_device *bdev,
433 struct blk_user_trace_setup *buts)
434 {
435 struct blk_trace *old_bt, *bt = NULL;
436 struct dentry *dir = NULL;
437 int ret, i;
438
439 if (!buts->buf_size || !buts->buf_nr)
440 return -EINVAL;
441
442 strncpy(buts->name, name, BLKTRACE_BDEV_SIZE);
443 buts->name[BLKTRACE_BDEV_SIZE - 1] = '\0';
444
445 /*
446 * some device names have larger paths - convert the slashes
447 * to underscores for this to work as expected
448 */
449 for (i = 0; i < strlen(buts->name); i++)
450 if (buts->name[i] == '/')
451 buts->name[i] = '_';
452
453 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
454 if (!bt)
455 return -ENOMEM;
456
457 ret = -ENOMEM;
458 bt->sequence = alloc_percpu(unsigned long);
459 if (!bt->sequence)
460 goto err;
461
462 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
463 if (!bt->msg_data)
464 goto err;
465
466 ret = -ENOENT;
467
468 mutex_lock(&blk_tree_mutex);
469 if (!blk_tree_root) {
470 blk_tree_root = debugfs_create_dir("block", NULL);
471 if (!blk_tree_root) {
472 mutex_unlock(&blk_tree_mutex);
473 goto err;
474 }
475 }
476 mutex_unlock(&blk_tree_mutex);
477
478 dir = debugfs_create_dir(buts->name, blk_tree_root);
479
480 if (!dir)
481 goto err;
482
483 bt->dir = dir;
484 bt->dev = dev;
485 atomic_set(&bt->dropped, 0);
486
487 ret = -EIO;
488 bt->dropped_file = debugfs_create_file("dropped", 0444, dir, bt,
489 &blk_dropped_fops);
490 if (!bt->dropped_file)
491 goto err;
492
493 bt->msg_file = debugfs_create_file("msg", 0222, dir, bt, &blk_msg_fops);
494 if (!bt->msg_file)
495 goto err;
496
497 bt->rchan = relay_open("trace", dir, buts->buf_size,
498 buts->buf_nr, &blk_relay_callbacks, bt);
499 if (!bt->rchan)
500 goto err;
501
502 bt->act_mask = buts->act_mask;
503 if (!bt->act_mask)
504 bt->act_mask = (u16) -1;
505
506 blk_trace_setup_lba(bt, bdev);
507
508 /* overwrite with user settings */
509 if (buts->start_lba)
510 bt->start_lba = buts->start_lba;
511 if (buts->end_lba)
512 bt->end_lba = buts->end_lba;
513
514 bt->pid = buts->pid;
515 bt->trace_state = Blktrace_setup;
516
517 ret = -EBUSY;
518 old_bt = xchg(&q->blk_trace, bt);
519 if (old_bt) {
520 (void) xchg(&q->blk_trace, old_bt);
521 goto err;
522 }
523
524 if (atomic_inc_return(&blk_probes_ref) == 1)
525 blk_register_tracepoints();
526
527 return 0;
528 err:
529 blk_trace_free(bt);
530 return ret;
531 }
532
533 int blk_trace_setup(struct request_queue *q, char *name, dev_t dev,
534 struct block_device *bdev,
535 char __user *arg)
536 {
537 struct blk_user_trace_setup buts;
538 int ret;
539
540 ret = copy_from_user(&buts, arg, sizeof(buts));
541 if (ret)
542 return -EFAULT;
543
544 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
545 if (ret)
546 return ret;
547
548 if (copy_to_user(arg, &buts, sizeof(buts))) {
549 blk_trace_remove(q);
550 return -EFAULT;
551 }
552 return 0;
553 }
554 EXPORT_SYMBOL_GPL(blk_trace_setup);
555
556 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
557 static int compat_blk_trace_setup(struct request_queue *q, char *name,
558 dev_t dev, struct block_device *bdev,
559 char __user *arg)
560 {
561 struct blk_user_trace_setup buts;
562 struct compat_blk_user_trace_setup cbuts;
563 int ret;
564
565 if (copy_from_user(&cbuts, arg, sizeof(cbuts)))
566 return -EFAULT;
567
568 buts = (struct blk_user_trace_setup) {
569 .act_mask = cbuts.act_mask,
570 .buf_size = cbuts.buf_size,
571 .buf_nr = cbuts.buf_nr,
572 .start_lba = cbuts.start_lba,
573 .end_lba = cbuts.end_lba,
574 .pid = cbuts.pid,
575 };
576 memcpy(&buts.name, &cbuts.name, 32);
577
578 ret = do_blk_trace_setup(q, name, dev, bdev, &buts);
579 if (ret)
580 return ret;
581
582 if (copy_to_user(arg, &buts.name, 32)) {
583 blk_trace_remove(q);
584 return -EFAULT;
585 }
586
587 return 0;
588 }
589 #endif
590
591 int blk_trace_startstop(struct request_queue *q, int start)
592 {
593 int ret;
594 struct blk_trace *bt = q->blk_trace;
595
596 if (bt == NULL)
597 return -EINVAL;
598
599 /*
600 * For starting a trace, we can transition from a setup or stopped
601 * trace. For stopping a trace, the state must be running
602 */
603 ret = -EINVAL;
604 if (start) {
605 if (bt->trace_state == Blktrace_setup ||
606 bt->trace_state == Blktrace_stopped) {
607 blktrace_seq++;
608 smp_mb();
609 bt->trace_state = Blktrace_running;
610
611 trace_note_time(bt);
612 ret = 0;
613 }
614 } else {
615 if (bt->trace_state == Blktrace_running) {
616 bt->trace_state = Blktrace_stopped;
617 relay_flush(bt->rchan);
618 ret = 0;
619 }
620 }
621
622 return ret;
623 }
624 EXPORT_SYMBOL_GPL(blk_trace_startstop);
625
626 /**
627 * blk_trace_ioctl: - handle the ioctls associated with tracing
628 * @bdev: the block device
629 * @cmd: the ioctl cmd
630 * @arg: the argument data, if any
631 *
632 **/
633 int blk_trace_ioctl(struct block_device *bdev, unsigned cmd, char __user *arg)
634 {
635 struct request_queue *q;
636 int ret, start = 0;
637 char b[BDEVNAME_SIZE];
638
639 q = bdev_get_queue(bdev);
640 if (!q)
641 return -ENXIO;
642
643 mutex_lock(&bdev->bd_mutex);
644
645 switch (cmd) {
646 case BLKTRACESETUP:
647 bdevname(bdev, b);
648 ret = blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
649 break;
650 #if defined(CONFIG_COMPAT) && defined(CONFIG_X86_64)
651 case BLKTRACESETUP32:
652 bdevname(bdev, b);
653 ret = compat_blk_trace_setup(q, b, bdev->bd_dev, bdev, arg);
654 break;
655 #endif
656 case BLKTRACESTART:
657 start = 1;
658 case BLKTRACESTOP:
659 ret = blk_trace_startstop(q, start);
660 break;
661 case BLKTRACETEARDOWN:
662 ret = blk_trace_remove(q);
663 break;
664 default:
665 ret = -ENOTTY;
666 break;
667 }
668
669 mutex_unlock(&bdev->bd_mutex);
670 return ret;
671 }
672
673 /**
674 * blk_trace_shutdown: - stop and cleanup trace structures
675 * @q: the request queue associated with the device
676 *
677 **/
678 void blk_trace_shutdown(struct request_queue *q)
679 {
680 if (q->blk_trace) {
681 blk_trace_startstop(q, 0);
682 blk_trace_remove(q);
683 }
684 }
685
686 /*
687 * blktrace probes
688 */
689
690 /**
691 * blk_add_trace_rq - Add a trace for a request oriented action
692 * @q: queue the io is for
693 * @rq: the source request
694 * @what: the action
695 *
696 * Description:
697 * Records an action against a request. Will log the bio offset + size.
698 *
699 **/
700 static void blk_add_trace_rq(struct request_queue *q, struct request *rq,
701 u32 what)
702 {
703 struct blk_trace *bt = q->blk_trace;
704 int rw = rq->cmd_flags & 0x03;
705
706 if (likely(!bt))
707 return;
708
709 if (rq->cmd_flags & REQ_DISCARD)
710 rw |= REQ_DISCARD;
711
712 if (rq->cmd_flags & REQ_SECURE)
713 rw |= REQ_SECURE;
714
715 if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
716 what |= BLK_TC_ACT(BLK_TC_PC);
717 __blk_add_trace(bt, 0, blk_rq_bytes(rq), rw,
718 what, rq->errors, rq->cmd_len, rq->cmd);
719 } else {
720 what |= BLK_TC_ACT(BLK_TC_FS);
721 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), rw,
722 what, rq->errors, 0, NULL);
723 }
724 }
725
726 static void blk_add_trace_rq_abort(void *ignore,
727 struct request_queue *q, struct request *rq)
728 {
729 blk_add_trace_rq(q, rq, BLK_TA_ABORT);
730 }
731
732 static void blk_add_trace_rq_insert(void *ignore,
733 struct request_queue *q, struct request *rq)
734 {
735 blk_add_trace_rq(q, rq, BLK_TA_INSERT);
736 }
737
738 static void blk_add_trace_rq_issue(void *ignore,
739 struct request_queue *q, struct request *rq)
740 {
741 blk_add_trace_rq(q, rq, BLK_TA_ISSUE);
742 }
743
744 static void blk_add_trace_rq_requeue(void *ignore,
745 struct request_queue *q,
746 struct request *rq)
747 {
748 blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
749 }
750
751 static void blk_add_trace_rq_complete(void *ignore,
752 struct request_queue *q,
753 struct request *rq)
754 {
755 blk_add_trace_rq(q, rq, BLK_TA_COMPLETE);
756 }
757
758 /**
759 * blk_add_trace_bio - Add a trace for a bio oriented action
760 * @q: queue the io is for
761 * @bio: the source bio
762 * @what: the action
763 *
764 * Description:
765 * Records an action against a bio. Will log the bio offset + size.
766 *
767 **/
768 static void blk_add_trace_bio(struct request_queue *q, struct bio *bio,
769 u32 what)
770 {
771 struct blk_trace *bt = q->blk_trace;
772
773 if (likely(!bt))
774 return;
775
776 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw, what,
777 !bio_flagged(bio, BIO_UPTODATE), 0, NULL);
778 }
779
780 static void blk_add_trace_bio_bounce(void *ignore,
781 struct request_queue *q, struct bio *bio)
782 {
783 blk_add_trace_bio(q, bio, BLK_TA_BOUNCE);
784 }
785
786 static void blk_add_trace_bio_complete(void *ignore,
787 struct request_queue *q, struct bio *bio)
788 {
789 blk_add_trace_bio(q, bio, BLK_TA_COMPLETE);
790 }
791
792 static void blk_add_trace_bio_backmerge(void *ignore,
793 struct request_queue *q,
794 struct bio *bio)
795 {
796 blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
797 }
798
799 static void blk_add_trace_bio_frontmerge(void *ignore,
800 struct request_queue *q,
801 struct bio *bio)
802 {
803 blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
804 }
805
806 static void blk_add_trace_bio_queue(void *ignore,
807 struct request_queue *q, struct bio *bio)
808 {
809 blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
810 }
811
812 static void blk_add_trace_getrq(void *ignore,
813 struct request_queue *q,
814 struct bio *bio, int rw)
815 {
816 if (bio)
817 blk_add_trace_bio(q, bio, BLK_TA_GETRQ);
818 else {
819 struct blk_trace *bt = q->blk_trace;
820
821 if (bt)
822 __blk_add_trace(bt, 0, 0, rw, BLK_TA_GETRQ, 0, 0, NULL);
823 }
824 }
825
826
827 static void blk_add_trace_sleeprq(void *ignore,
828 struct request_queue *q,
829 struct bio *bio, int rw)
830 {
831 if (bio)
832 blk_add_trace_bio(q, bio, BLK_TA_SLEEPRQ);
833 else {
834 struct blk_trace *bt = q->blk_trace;
835
836 if (bt)
837 __blk_add_trace(bt, 0, 0, rw, BLK_TA_SLEEPRQ,
838 0, 0, NULL);
839 }
840 }
841
842 static void blk_add_trace_plug(void *ignore, struct request_queue *q)
843 {
844 struct blk_trace *bt = q->blk_trace;
845
846 if (bt)
847 __blk_add_trace(bt, 0, 0, 0, BLK_TA_PLUG, 0, 0, NULL);
848 }
849
850 static void blk_add_trace_unplug_io(void *ignore, struct request_queue *q)
851 {
852 struct blk_trace *bt = q->blk_trace;
853
854 if (bt) {
855 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
856 __be64 rpdu = cpu_to_be64(pdu);
857
858 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_IO, 0,
859 sizeof(rpdu), &rpdu);
860 }
861 }
862
863 static void blk_add_trace_unplug_timer(void *ignore, struct request_queue *q)
864 {
865 struct blk_trace *bt = q->blk_trace;
866
867 if (bt) {
868 unsigned int pdu = q->rq.count[READ] + q->rq.count[WRITE];
869 __be64 rpdu = cpu_to_be64(pdu);
870
871 __blk_add_trace(bt, 0, 0, 0, BLK_TA_UNPLUG_TIMER, 0,
872 sizeof(rpdu), &rpdu);
873 }
874 }
875
876 static void blk_add_trace_split(void *ignore,
877 struct request_queue *q, struct bio *bio,
878 unsigned int pdu)
879 {
880 struct blk_trace *bt = q->blk_trace;
881
882 if (bt) {
883 __be64 rpdu = cpu_to_be64(pdu);
884
885 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
886 BLK_TA_SPLIT, !bio_flagged(bio, BIO_UPTODATE),
887 sizeof(rpdu), &rpdu);
888 }
889 }
890
891 /**
892 * blk_add_trace_remap - Add a trace for a remap operation
893 * @ignore: trace callback data parameter (not used)
894 * @q: queue the io is for
895 * @bio: the source bio
896 * @dev: target device
897 * @from: source sector
898 *
899 * Description:
900 * Device mapper or raid target sometimes need to split a bio because
901 * it spans a stripe (or similar). Add a trace for that action.
902 *
903 **/
904 static void blk_add_trace_remap(void *ignore,
905 struct request_queue *q, struct bio *bio,
906 dev_t dev, sector_t from)
907 {
908 struct blk_trace *bt = q->blk_trace;
909 struct blk_io_trace_remap r;
910
911 if (likely(!bt))
912 return;
913
914 r.device_from = cpu_to_be32(dev);
915 r.device_to = cpu_to_be32(bio->bi_bdev->bd_dev);
916 r.sector_from = cpu_to_be64(from);
917
918 __blk_add_trace(bt, bio->bi_sector, bio->bi_size, bio->bi_rw,
919 BLK_TA_REMAP, !bio_flagged(bio, BIO_UPTODATE),
920 sizeof(r), &r);
921 }
922
923 /**
924 * blk_add_trace_rq_remap - Add a trace for a request-remap operation
925 * @ignore: trace callback data parameter (not used)
926 * @q: queue the io is for
927 * @rq: the source request
928 * @dev: target device
929 * @from: source sector
930 *
931 * Description:
932 * Device mapper remaps request to other devices.
933 * Add a trace for that action.
934 *
935 **/
936 static void blk_add_trace_rq_remap(void *ignore,
937 struct request_queue *q,
938 struct request *rq, dev_t dev,
939 sector_t from)
940 {
941 struct blk_trace *bt = q->blk_trace;
942 struct blk_io_trace_remap r;
943
944 if (likely(!bt))
945 return;
946
947 r.device_from = cpu_to_be32(dev);
948 r.device_to = cpu_to_be32(disk_devt(rq->rq_disk));
949 r.sector_from = cpu_to_be64(from);
950
951 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq),
952 rq_data_dir(rq), BLK_TA_REMAP, !!rq->errors,
953 sizeof(r), &r);
954 }
955
956 /**
957 * blk_add_driver_data - Add binary message with driver-specific data
958 * @q: queue the io is for
959 * @rq: io request
960 * @data: driver-specific data
961 * @len: length of driver-specific data
962 *
963 * Description:
964 * Some drivers might want to write driver-specific data per request.
965 *
966 **/
967 void blk_add_driver_data(struct request_queue *q,
968 struct request *rq,
969 void *data, size_t len)
970 {
971 struct blk_trace *bt = q->blk_trace;
972
973 if (likely(!bt))
974 return;
975
976 if (rq->cmd_type == REQ_TYPE_BLOCK_PC)
977 __blk_add_trace(bt, 0, blk_rq_bytes(rq), 0,
978 BLK_TA_DRV_DATA, rq->errors, len, data);
979 else
980 __blk_add_trace(bt, blk_rq_pos(rq), blk_rq_bytes(rq), 0,
981 BLK_TA_DRV_DATA, rq->errors, len, data);
982 }
983 EXPORT_SYMBOL_GPL(blk_add_driver_data);
984
985 static void blk_register_tracepoints(void)
986 {
987 int ret;
988
989 ret = register_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
990 WARN_ON(ret);
991 ret = register_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
992 WARN_ON(ret);
993 ret = register_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
994 WARN_ON(ret);
995 ret = register_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
996 WARN_ON(ret);
997 ret = register_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
998 WARN_ON(ret);
999 ret = register_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1000 WARN_ON(ret);
1001 ret = register_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1002 WARN_ON(ret);
1003 ret = register_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1004 WARN_ON(ret);
1005 ret = register_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1006 WARN_ON(ret);
1007 ret = register_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1008 WARN_ON(ret);
1009 ret = register_trace_block_getrq(blk_add_trace_getrq, NULL);
1010 WARN_ON(ret);
1011 ret = register_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1012 WARN_ON(ret);
1013 ret = register_trace_block_plug(blk_add_trace_plug, NULL);
1014 WARN_ON(ret);
1015 ret = register_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
1016 WARN_ON(ret);
1017 ret = register_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
1018 WARN_ON(ret);
1019 ret = register_trace_block_split(blk_add_trace_split, NULL);
1020 WARN_ON(ret);
1021 ret = register_trace_block_remap(blk_add_trace_remap, NULL);
1022 WARN_ON(ret);
1023 ret = register_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1024 WARN_ON(ret);
1025 }
1026
1027 static void blk_unregister_tracepoints(void)
1028 {
1029 unregister_trace_block_rq_remap(blk_add_trace_rq_remap, NULL);
1030 unregister_trace_block_remap(blk_add_trace_remap, NULL);
1031 unregister_trace_block_split(blk_add_trace_split, NULL);
1032 unregister_trace_block_unplug_io(blk_add_trace_unplug_io, NULL);
1033 unregister_trace_block_unplug_timer(blk_add_trace_unplug_timer, NULL);
1034 unregister_trace_block_plug(blk_add_trace_plug, NULL);
1035 unregister_trace_block_sleeprq(blk_add_trace_sleeprq, NULL);
1036 unregister_trace_block_getrq(blk_add_trace_getrq, NULL);
1037 unregister_trace_block_bio_queue(blk_add_trace_bio_queue, NULL);
1038 unregister_trace_block_bio_frontmerge(blk_add_trace_bio_frontmerge, NULL);
1039 unregister_trace_block_bio_backmerge(blk_add_trace_bio_backmerge, NULL);
1040 unregister_trace_block_bio_complete(blk_add_trace_bio_complete, NULL);
1041 unregister_trace_block_bio_bounce(blk_add_trace_bio_bounce, NULL);
1042 unregister_trace_block_rq_complete(blk_add_trace_rq_complete, NULL);
1043 unregister_trace_block_rq_requeue(blk_add_trace_rq_requeue, NULL);
1044 unregister_trace_block_rq_issue(blk_add_trace_rq_issue, NULL);
1045 unregister_trace_block_rq_insert(blk_add_trace_rq_insert, NULL);
1046 unregister_trace_block_rq_abort(blk_add_trace_rq_abort, NULL);
1047
1048 tracepoint_synchronize_unregister();
1049 }
1050
1051 /*
1052 * struct blk_io_tracer formatting routines
1053 */
1054
1055 static void fill_rwbs(char *rwbs, const struct blk_io_trace *t)
1056 {
1057 int i = 0;
1058 int tc = t->action >> BLK_TC_SHIFT;
1059
1060 if (t->action == BLK_TN_MESSAGE) {
1061 rwbs[i++] = 'N';
1062 goto out;
1063 }
1064
1065 if (tc & BLK_TC_DISCARD)
1066 rwbs[i++] = 'D';
1067 else if (tc & BLK_TC_WRITE)
1068 rwbs[i++] = 'W';
1069 else if (t->bytes)
1070 rwbs[i++] = 'R';
1071 else
1072 rwbs[i++] = 'N';
1073
1074 if (tc & BLK_TC_AHEAD)
1075 rwbs[i++] = 'A';
1076 if (tc & BLK_TC_BARRIER)
1077 rwbs[i++] = 'B';
1078 if (tc & BLK_TC_SYNC)
1079 rwbs[i++] = 'S';
1080 if (tc & BLK_TC_META)
1081 rwbs[i++] = 'M';
1082 out:
1083 rwbs[i] = '\0';
1084 }
1085
1086 static inline
1087 const struct blk_io_trace *te_blk_io_trace(const struct trace_entry *ent)
1088 {
1089 return (const struct blk_io_trace *)ent;
1090 }
1091
1092 static inline const void *pdu_start(const struct trace_entry *ent)
1093 {
1094 return te_blk_io_trace(ent) + 1;
1095 }
1096
1097 static inline u32 t_action(const struct trace_entry *ent)
1098 {
1099 return te_blk_io_trace(ent)->action;
1100 }
1101
1102 static inline u32 t_bytes(const struct trace_entry *ent)
1103 {
1104 return te_blk_io_trace(ent)->bytes;
1105 }
1106
1107 static inline u32 t_sec(const struct trace_entry *ent)
1108 {
1109 return te_blk_io_trace(ent)->bytes >> 9;
1110 }
1111
1112 static inline unsigned long long t_sector(const struct trace_entry *ent)
1113 {
1114 return te_blk_io_trace(ent)->sector;
1115 }
1116
1117 static inline __u16 t_error(const struct trace_entry *ent)
1118 {
1119 return te_blk_io_trace(ent)->error;
1120 }
1121
1122 static __u64 get_pdu_int(const struct trace_entry *ent)
1123 {
1124 const __u64 *val = pdu_start(ent);
1125 return be64_to_cpu(*val);
1126 }
1127
1128 static void get_pdu_remap(const struct trace_entry *ent,
1129 struct blk_io_trace_remap *r)
1130 {
1131 const struct blk_io_trace_remap *__r = pdu_start(ent);
1132 __u64 sector_from = __r->sector_from;
1133
1134 r->device_from = be32_to_cpu(__r->device_from);
1135 r->device_to = be32_to_cpu(__r->device_to);
1136 r->sector_from = be64_to_cpu(sector_from);
1137 }
1138
1139 typedef int (blk_log_action_t) (struct trace_iterator *iter, const char *act);
1140
1141 static int blk_log_action_classic(struct trace_iterator *iter, const char *act)
1142 {
1143 char rwbs[6];
1144 unsigned long long ts = iter->ts;
1145 unsigned long nsec_rem = do_div(ts, NSEC_PER_SEC);
1146 unsigned secs = (unsigned long)ts;
1147 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1148
1149 fill_rwbs(rwbs, t);
1150
1151 return trace_seq_printf(&iter->seq,
1152 "%3d,%-3d %2d %5d.%09lu %5u %2s %3s ",
1153 MAJOR(t->device), MINOR(t->device), iter->cpu,
1154 secs, nsec_rem, iter->ent->pid, act, rwbs);
1155 }
1156
1157 static int blk_log_action(struct trace_iterator *iter, const char *act)
1158 {
1159 char rwbs[6];
1160 const struct blk_io_trace *t = te_blk_io_trace(iter->ent);
1161
1162 fill_rwbs(rwbs, t);
1163 return trace_seq_printf(&iter->seq, "%3d,%-3d %2s %3s ",
1164 MAJOR(t->device), MINOR(t->device), act, rwbs);
1165 }
1166
1167 static int blk_log_dump_pdu(struct trace_seq *s, const struct trace_entry *ent)
1168 {
1169 const unsigned char *pdu_buf;
1170 int pdu_len;
1171 int i, end, ret;
1172
1173 pdu_buf = pdu_start(ent);
1174 pdu_len = te_blk_io_trace(ent)->pdu_len;
1175
1176 if (!pdu_len)
1177 return 1;
1178
1179 /* find the last zero that needs to be printed */
1180 for (end = pdu_len - 1; end >= 0; end--)
1181 if (pdu_buf[end])
1182 break;
1183 end++;
1184
1185 if (!trace_seq_putc(s, '('))
1186 return 0;
1187
1188 for (i = 0; i < pdu_len; i++) {
1189
1190 ret = trace_seq_printf(s, "%s%02x",
1191 i == 0 ? "" : " ", pdu_buf[i]);
1192 if (!ret)
1193 return ret;
1194
1195 /*
1196 * stop when the rest is just zeroes and indicate so
1197 * with a ".." appended
1198 */
1199 if (i == end && end != pdu_len - 1)
1200 return trace_seq_puts(s, " ..) ");
1201 }
1202
1203 return trace_seq_puts(s, ") ");
1204 }
1205
1206 static int blk_log_generic(struct trace_seq *s, const struct trace_entry *ent)
1207 {
1208 char cmd[TASK_COMM_LEN];
1209
1210 trace_find_cmdline(ent->pid, cmd);
1211
1212 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1213 int ret;
1214
1215 ret = trace_seq_printf(s, "%u ", t_bytes(ent));
1216 if (!ret)
1217 return 0;
1218 ret = blk_log_dump_pdu(s, ent);
1219 if (!ret)
1220 return 0;
1221 return trace_seq_printf(s, "[%s]\n", cmd);
1222 } else {
1223 if (t_sec(ent))
1224 return trace_seq_printf(s, "%llu + %u [%s]\n",
1225 t_sector(ent), t_sec(ent), cmd);
1226 return trace_seq_printf(s, "[%s]\n", cmd);
1227 }
1228 }
1229
1230 static int blk_log_with_error(struct trace_seq *s,
1231 const struct trace_entry *ent)
1232 {
1233 if (t_action(ent) & BLK_TC_ACT(BLK_TC_PC)) {
1234 int ret;
1235
1236 ret = blk_log_dump_pdu(s, ent);
1237 if (ret)
1238 return trace_seq_printf(s, "[%d]\n", t_error(ent));
1239 return 0;
1240 } else {
1241 if (t_sec(ent))
1242 return trace_seq_printf(s, "%llu + %u [%d]\n",
1243 t_sector(ent),
1244 t_sec(ent), t_error(ent));
1245 return trace_seq_printf(s, "%llu [%d]\n",
1246 t_sector(ent), t_error(ent));
1247 }
1248 }
1249
1250 static int blk_log_remap(struct trace_seq *s, const struct trace_entry *ent)
1251 {
1252 struct blk_io_trace_remap r = { .device_from = 0, };
1253
1254 get_pdu_remap(ent, &r);
1255 return trace_seq_printf(s, "%llu + %u <- (%d,%d) %llu\n",
1256 t_sector(ent), t_sec(ent),
1257 MAJOR(r.device_from), MINOR(r.device_from),
1258 (unsigned long long)r.sector_from);
1259 }
1260
1261 static int blk_log_plug(struct trace_seq *s, const struct trace_entry *ent)
1262 {
1263 char cmd[TASK_COMM_LEN];
1264
1265 trace_find_cmdline(ent->pid, cmd);
1266
1267 return trace_seq_printf(s, "[%s]\n", cmd);
1268 }
1269
1270 static int blk_log_unplug(struct trace_seq *s, const struct trace_entry *ent)
1271 {
1272 char cmd[TASK_COMM_LEN];
1273
1274 trace_find_cmdline(ent->pid, cmd);
1275
1276 return trace_seq_printf(s, "[%s] %llu\n", cmd, get_pdu_int(ent));
1277 }
1278
1279 static int blk_log_split(struct trace_seq *s, const struct trace_entry *ent)
1280 {
1281 char cmd[TASK_COMM_LEN];
1282
1283 trace_find_cmdline(ent->pid, cmd);
1284
1285 return trace_seq_printf(s, "%llu / %llu [%s]\n", t_sector(ent),
1286 get_pdu_int(ent), cmd);
1287 }
1288
1289 static int blk_log_msg(struct trace_seq *s, const struct trace_entry *ent)
1290 {
1291 int ret;
1292 const struct blk_io_trace *t = te_blk_io_trace(ent);
1293
1294 ret = trace_seq_putmem(s, t + 1, t->pdu_len);
1295 if (ret)
1296 return trace_seq_putc(s, '\n');
1297 return ret;
1298 }
1299
1300 /*
1301 * struct tracer operations
1302 */
1303
1304 static void blk_tracer_print_header(struct seq_file *m)
1305 {
1306 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1307 return;
1308 seq_puts(m, "# DEV CPU TIMESTAMP PID ACT FLG\n"
1309 "# | | | | | |\n");
1310 }
1311
1312 static void blk_tracer_start(struct trace_array *tr)
1313 {
1314 blk_tracer_enabled = true;
1315 }
1316
1317 static int blk_tracer_init(struct trace_array *tr)
1318 {
1319 blk_tr = tr;
1320 blk_tracer_start(tr);
1321 return 0;
1322 }
1323
1324 static void blk_tracer_stop(struct trace_array *tr)
1325 {
1326 blk_tracer_enabled = false;
1327 }
1328
1329 static void blk_tracer_reset(struct trace_array *tr)
1330 {
1331 blk_tracer_stop(tr);
1332 }
1333
1334 static const struct {
1335 const char *act[2];
1336 int (*print)(struct trace_seq *s, const struct trace_entry *ent);
1337 } what2act[] = {
1338 [__BLK_TA_QUEUE] = {{ "Q", "queue" }, blk_log_generic },
1339 [__BLK_TA_BACKMERGE] = {{ "M", "backmerge" }, blk_log_generic },
1340 [__BLK_TA_FRONTMERGE] = {{ "F", "frontmerge" }, blk_log_generic },
1341 [__BLK_TA_GETRQ] = {{ "G", "getrq" }, blk_log_generic },
1342 [__BLK_TA_SLEEPRQ] = {{ "S", "sleeprq" }, blk_log_generic },
1343 [__BLK_TA_REQUEUE] = {{ "R", "requeue" }, blk_log_with_error },
1344 [__BLK_TA_ISSUE] = {{ "D", "issue" }, blk_log_generic },
1345 [__BLK_TA_COMPLETE] = {{ "C", "complete" }, blk_log_with_error },
1346 [__BLK_TA_PLUG] = {{ "P", "plug" }, blk_log_plug },
1347 [__BLK_TA_UNPLUG_IO] = {{ "U", "unplug_io" }, blk_log_unplug },
1348 [__BLK_TA_UNPLUG_TIMER] = {{ "UT", "unplug_timer" }, blk_log_unplug },
1349 [__BLK_TA_INSERT] = {{ "I", "insert" }, blk_log_generic },
1350 [__BLK_TA_SPLIT] = {{ "X", "split" }, blk_log_split },
1351 [__BLK_TA_BOUNCE] = {{ "B", "bounce" }, blk_log_generic },
1352 [__BLK_TA_REMAP] = {{ "A", "remap" }, blk_log_remap },
1353 };
1354
1355 static enum print_line_t print_one_line(struct trace_iterator *iter,
1356 bool classic)
1357 {
1358 struct trace_seq *s = &iter->seq;
1359 const struct blk_io_trace *t;
1360 u16 what;
1361 int ret;
1362 bool long_act;
1363 blk_log_action_t *log_action;
1364
1365 t = te_blk_io_trace(iter->ent);
1366 what = t->action & ((1 << BLK_TC_SHIFT) - 1);
1367 long_act = !!(trace_flags & TRACE_ITER_VERBOSE);
1368 log_action = classic ? &blk_log_action_classic : &blk_log_action;
1369
1370 if (t->action == BLK_TN_MESSAGE) {
1371 ret = log_action(iter, long_act ? "message" : "m");
1372 if (ret)
1373 ret = blk_log_msg(s, iter->ent);
1374 goto out;
1375 }
1376
1377 if (unlikely(what == 0 || what >= ARRAY_SIZE(what2act)))
1378 ret = trace_seq_printf(s, "Unknown action %x\n", what);
1379 else {
1380 ret = log_action(iter, what2act[what].act[long_act]);
1381 if (ret)
1382 ret = what2act[what].print(s, iter->ent);
1383 }
1384 out:
1385 return ret ? TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1386 }
1387
1388 static enum print_line_t blk_trace_event_print(struct trace_iterator *iter,
1389 int flags, struct trace_event *event)
1390 {
1391 return print_one_line(iter, false);
1392 }
1393
1394 static int blk_trace_synthesize_old_trace(struct trace_iterator *iter)
1395 {
1396 struct trace_seq *s = &iter->seq;
1397 struct blk_io_trace *t = (struct blk_io_trace *)iter->ent;
1398 const int offset = offsetof(struct blk_io_trace, sector);
1399 struct blk_io_trace old = {
1400 .magic = BLK_IO_TRACE_MAGIC | BLK_IO_TRACE_VERSION,
1401 .time = iter->ts,
1402 };
1403
1404 if (!trace_seq_putmem(s, &old, offset))
1405 return 0;
1406 return trace_seq_putmem(s, &t->sector,
1407 sizeof(old) - offset + t->pdu_len);
1408 }
1409
1410 static enum print_line_t
1411 blk_trace_event_print_binary(struct trace_iterator *iter, int flags,
1412 struct trace_event *event)
1413 {
1414 return blk_trace_synthesize_old_trace(iter) ?
1415 TRACE_TYPE_HANDLED : TRACE_TYPE_PARTIAL_LINE;
1416 }
1417
1418 static enum print_line_t blk_tracer_print_line(struct trace_iterator *iter)
1419 {
1420 if (!(blk_tracer_flags.val & TRACE_BLK_OPT_CLASSIC))
1421 return TRACE_TYPE_UNHANDLED;
1422
1423 return print_one_line(iter, true);
1424 }
1425
1426 static int blk_tracer_set_flag(u32 old_flags, u32 bit, int set)
1427 {
1428 /* don't output context-info for blk_classic output */
1429 if (bit == TRACE_BLK_OPT_CLASSIC) {
1430 if (set)
1431 trace_flags &= ~TRACE_ITER_CONTEXT_INFO;
1432 else
1433 trace_flags |= TRACE_ITER_CONTEXT_INFO;
1434 }
1435 return 0;
1436 }
1437
1438 static struct tracer blk_tracer __read_mostly = {
1439 .name = "blk",
1440 .init = blk_tracer_init,
1441 .reset = blk_tracer_reset,
1442 .start = blk_tracer_start,
1443 .stop = blk_tracer_stop,
1444 .print_header = blk_tracer_print_header,
1445 .print_line = blk_tracer_print_line,
1446 .flags = &blk_tracer_flags,
1447 .set_flag = blk_tracer_set_flag,
1448 };
1449
1450 static struct trace_event_functions trace_blk_event_funcs = {
1451 .trace = blk_trace_event_print,
1452 .binary = blk_trace_event_print_binary,
1453 };
1454
1455 static struct trace_event trace_blk_event = {
1456 .type = TRACE_BLK,
1457 .funcs = &trace_blk_event_funcs,
1458 };
1459
1460 static int __init init_blk_tracer(void)
1461 {
1462 if (!register_ftrace_event(&trace_blk_event)) {
1463 pr_warning("Warning: could not register block events\n");
1464 return 1;
1465 }
1466
1467 if (register_tracer(&blk_tracer) != 0) {
1468 pr_warning("Warning: could not register the block tracer\n");
1469 unregister_ftrace_event(&trace_blk_event);
1470 return 1;
1471 }
1472
1473 return 0;
1474 }
1475
1476 device_initcall(init_blk_tracer);
1477
1478 static int blk_trace_remove_queue(struct request_queue *q)
1479 {
1480 struct blk_trace *bt;
1481
1482 bt = xchg(&q->blk_trace, NULL);
1483 if (bt == NULL)
1484 return -EINVAL;
1485
1486 if (atomic_dec_and_test(&blk_probes_ref))
1487 blk_unregister_tracepoints();
1488
1489 blk_trace_free(bt);
1490 return 0;
1491 }
1492
1493 /*
1494 * Setup everything required to start tracing
1495 */
1496 static int blk_trace_setup_queue(struct request_queue *q,
1497 struct block_device *bdev)
1498 {
1499 struct blk_trace *old_bt, *bt = NULL;
1500 int ret = -ENOMEM;
1501
1502 bt = kzalloc(sizeof(*bt), GFP_KERNEL);
1503 if (!bt)
1504 return -ENOMEM;
1505
1506 bt->msg_data = __alloc_percpu(BLK_TN_MAX_MSG, __alignof__(char));
1507 if (!bt->msg_data)
1508 goto free_bt;
1509
1510 bt->dev = bdev->bd_dev;
1511 bt->act_mask = (u16)-1;
1512
1513 blk_trace_setup_lba(bt, bdev);
1514
1515 old_bt = xchg(&q->blk_trace, bt);
1516 if (old_bt != NULL) {
1517 (void)xchg(&q->blk_trace, old_bt);
1518 ret = -EBUSY;
1519 goto free_bt;
1520 }
1521
1522 if (atomic_inc_return(&blk_probes_ref) == 1)
1523 blk_register_tracepoints();
1524 return 0;
1525
1526 free_bt:
1527 blk_trace_free(bt);
1528 return ret;
1529 }
1530
1531 /*
1532 * sysfs interface to enable and configure tracing
1533 */
1534
1535 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1536 struct device_attribute *attr,
1537 char *buf);
1538 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1539 struct device_attribute *attr,
1540 const char *buf, size_t count);
1541 #define BLK_TRACE_DEVICE_ATTR(_name) \
1542 DEVICE_ATTR(_name, S_IRUGO | S_IWUSR, \
1543 sysfs_blk_trace_attr_show, \
1544 sysfs_blk_trace_attr_store)
1545
1546 static BLK_TRACE_DEVICE_ATTR(enable);
1547 static BLK_TRACE_DEVICE_ATTR(act_mask);
1548 static BLK_TRACE_DEVICE_ATTR(pid);
1549 static BLK_TRACE_DEVICE_ATTR(start_lba);
1550 static BLK_TRACE_DEVICE_ATTR(end_lba);
1551
1552 static struct attribute *blk_trace_attrs[] = {
1553 &dev_attr_enable.attr,
1554 &dev_attr_act_mask.attr,
1555 &dev_attr_pid.attr,
1556 &dev_attr_start_lba.attr,
1557 &dev_attr_end_lba.attr,
1558 NULL
1559 };
1560
1561 struct attribute_group blk_trace_attr_group = {
1562 .name = "trace",
1563 .attrs = blk_trace_attrs,
1564 };
1565
1566 static const struct {
1567 int mask;
1568 const char *str;
1569 } mask_maps[] = {
1570 { BLK_TC_READ, "read" },
1571 { BLK_TC_WRITE, "write" },
1572 { BLK_TC_BARRIER, "barrier" },
1573 { BLK_TC_SYNC, "sync" },
1574 { BLK_TC_QUEUE, "queue" },
1575 { BLK_TC_REQUEUE, "requeue" },
1576 { BLK_TC_ISSUE, "issue" },
1577 { BLK_TC_COMPLETE, "complete" },
1578 { BLK_TC_FS, "fs" },
1579 { BLK_TC_PC, "pc" },
1580 { BLK_TC_AHEAD, "ahead" },
1581 { BLK_TC_META, "meta" },
1582 { BLK_TC_DISCARD, "discard" },
1583 { BLK_TC_DRV_DATA, "drv_data" },
1584 };
1585
1586 static int blk_trace_str2mask(const char *str)
1587 {
1588 int i;
1589 int mask = 0;
1590 char *buf, *s, *token;
1591
1592 buf = kstrdup(str, GFP_KERNEL);
1593 if (buf == NULL)
1594 return -ENOMEM;
1595 s = strstrip(buf);
1596
1597 while (1) {
1598 token = strsep(&s, ",");
1599 if (token == NULL)
1600 break;
1601
1602 if (*token == '\0')
1603 continue;
1604
1605 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1606 if (strcasecmp(token, mask_maps[i].str) == 0) {
1607 mask |= mask_maps[i].mask;
1608 break;
1609 }
1610 }
1611 if (i == ARRAY_SIZE(mask_maps)) {
1612 mask = -EINVAL;
1613 break;
1614 }
1615 }
1616 kfree(buf);
1617
1618 return mask;
1619 }
1620
1621 static ssize_t blk_trace_mask2str(char *buf, int mask)
1622 {
1623 int i;
1624 char *p = buf;
1625
1626 for (i = 0; i < ARRAY_SIZE(mask_maps); i++) {
1627 if (mask & mask_maps[i].mask) {
1628 p += sprintf(p, "%s%s",
1629 (p == buf) ? "" : ",", mask_maps[i].str);
1630 }
1631 }
1632 *p++ = '\n';
1633
1634 return p - buf;
1635 }
1636
1637 static struct request_queue *blk_trace_get_queue(struct block_device *bdev)
1638 {
1639 if (bdev->bd_disk == NULL)
1640 return NULL;
1641
1642 return bdev_get_queue(bdev);
1643 }
1644
1645 static ssize_t sysfs_blk_trace_attr_show(struct device *dev,
1646 struct device_attribute *attr,
1647 char *buf)
1648 {
1649 struct hd_struct *p = dev_to_part(dev);
1650 struct request_queue *q;
1651 struct block_device *bdev;
1652 ssize_t ret = -ENXIO;
1653
1654 bdev = bdget(part_devt(p));
1655 if (bdev == NULL)
1656 goto out;
1657
1658 q = blk_trace_get_queue(bdev);
1659 if (q == NULL)
1660 goto out_bdput;
1661
1662 mutex_lock(&bdev->bd_mutex);
1663
1664 if (attr == &dev_attr_enable) {
1665 ret = sprintf(buf, "%u\n", !!q->blk_trace);
1666 goto out_unlock_bdev;
1667 }
1668
1669 if (q->blk_trace == NULL)
1670 ret = sprintf(buf, "disabled\n");
1671 else if (attr == &dev_attr_act_mask)
1672 ret = blk_trace_mask2str(buf, q->blk_trace->act_mask);
1673 else if (attr == &dev_attr_pid)
1674 ret = sprintf(buf, "%u\n", q->blk_trace->pid);
1675 else if (attr == &dev_attr_start_lba)
1676 ret = sprintf(buf, "%llu\n", q->blk_trace->start_lba);
1677 else if (attr == &dev_attr_end_lba)
1678 ret = sprintf(buf, "%llu\n", q->blk_trace->end_lba);
1679
1680 out_unlock_bdev:
1681 mutex_unlock(&bdev->bd_mutex);
1682 out_bdput:
1683 bdput(bdev);
1684 out:
1685 return ret;
1686 }
1687
1688 static ssize_t sysfs_blk_trace_attr_store(struct device *dev,
1689 struct device_attribute *attr,
1690 const char *buf, size_t count)
1691 {
1692 struct block_device *bdev;
1693 struct request_queue *q;
1694 struct hd_struct *p;
1695 u64 value;
1696 ssize_t ret = -EINVAL;
1697
1698 if (count == 0)
1699 goto out;
1700
1701 if (attr == &dev_attr_act_mask) {
1702 if (sscanf(buf, "%llx", &value) != 1) {
1703 /* Assume it is a list of trace category names */
1704 ret = blk_trace_str2mask(buf);
1705 if (ret < 0)
1706 goto out;
1707 value = ret;
1708 }
1709 } else if (sscanf(buf, "%llu", &value) != 1)
1710 goto out;
1711
1712 ret = -ENXIO;
1713
1714 p = dev_to_part(dev);
1715 bdev = bdget(part_devt(p));
1716 if (bdev == NULL)
1717 goto out;
1718
1719 q = blk_trace_get_queue(bdev);
1720 if (q == NULL)
1721 goto out_bdput;
1722
1723 mutex_lock(&bdev->bd_mutex);
1724
1725 if (attr == &dev_attr_enable) {
1726 if (value)
1727 ret = blk_trace_setup_queue(q, bdev);
1728 else
1729 ret = blk_trace_remove_queue(q);
1730 goto out_unlock_bdev;
1731 }
1732
1733 ret = 0;
1734 if (q->blk_trace == NULL)
1735 ret = blk_trace_setup_queue(q, bdev);
1736
1737 if (ret == 0) {
1738 if (attr == &dev_attr_act_mask)
1739 q->blk_trace->act_mask = value;
1740 else if (attr == &dev_attr_pid)
1741 q->blk_trace->pid = value;
1742 else if (attr == &dev_attr_start_lba)
1743 q->blk_trace->start_lba = value;
1744 else if (attr == &dev_attr_end_lba)
1745 q->blk_trace->end_lba = value;
1746 }
1747
1748 out_unlock_bdev:
1749 mutex_unlock(&bdev->bd_mutex);
1750 out_bdput:
1751 bdput(bdev);
1752 out:
1753 return ret ? ret : count;
1754 }
1755
1756 int blk_trace_init_sysfs(struct device *dev)
1757 {
1758 return sysfs_create_group(&dev->kobj, &blk_trace_attr_group);
1759 }
1760
1761 void blk_trace_remove_sysfs(struct device *dev)
1762 {
1763 sysfs_remove_group(&dev->kobj, &blk_trace_attr_group);
1764 }
1765
1766 #endif /* CONFIG_BLK_DEV_IO_TRACE */
1767
1768 #ifdef CONFIG_EVENT_TRACING
1769
1770 void blk_dump_cmd(char *buf, struct request *rq)
1771 {
1772 int i, end;
1773 int len = rq->cmd_len;
1774 unsigned char *cmd = rq->cmd;
1775
1776 if (rq->cmd_type != REQ_TYPE_BLOCK_PC) {
1777 buf[0] = '\0';
1778 return;
1779 }
1780
1781 for (end = len - 1; end >= 0; end--)
1782 if (cmd[end])
1783 break;
1784 end++;
1785
1786 for (i = 0; i < len; i++) {
1787 buf += sprintf(buf, "%s%02x", i == 0 ? "" : " ", cmd[i]);
1788 if (i == end && end != len - 1) {
1789 sprintf(buf, " ..");
1790 break;
1791 }
1792 }
1793 }
1794
1795 void blk_fill_rwbs(char *rwbs, u32 rw, int bytes)
1796 {
1797 int i = 0;
1798
1799 if (rw & WRITE)
1800 rwbs[i++] = 'W';
1801 else if (rw & REQ_DISCARD)
1802 rwbs[i++] = 'D';
1803 else if (bytes)
1804 rwbs[i++] = 'R';
1805 else
1806 rwbs[i++] = 'N';
1807
1808 if (rw & REQ_RAHEAD)
1809 rwbs[i++] = 'A';
1810 if (rw & REQ_HARDBARRIER)
1811 rwbs[i++] = 'B';
1812 if (rw & REQ_SYNC)
1813 rwbs[i++] = 'S';
1814 if (rw & REQ_META)
1815 rwbs[i++] = 'M';
1816 if (rw & REQ_SECURE)
1817 rwbs[i++] = 'E';
1818
1819 rwbs[i] = '\0';
1820 }
1821
1822 void blk_fill_rwbs_rq(char *rwbs, struct request *rq)
1823 {
1824 int rw = rq->cmd_flags & 0x03;
1825 int bytes;
1826
1827 if (rq->cmd_flags & REQ_DISCARD)
1828 rw |= REQ_DISCARD;
1829
1830 if (rq->cmd_flags & REQ_SECURE)
1831 rw |= REQ_SECURE;
1832
1833 bytes = blk_rq_bytes(rq);
1834
1835 blk_fill_rwbs(rwbs, rw, bytes);
1836 }
1837
1838 #endif /* CONFIG_EVENT_TRACING */
1839
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